BRITISH LICHENS

218 OYOLOOARPINEJE LOPADIUM
glutinate, blackish at the apices; spores 8 in the ascus, oblong,
often narrowed at one or the other end, 22-40 (J. long, 10-18 (J.
thick; hymenial gelatine deep bluish with iodine.-L. 80ciale
Koerb. Parerg. Lich. 174 (1860). Biatora 80cialis Hepp ex
Koerb. 1. c. Lecidea fecunda Ny!. ex Stiz. Lich. Helv. 171
(1882); Cromb. in Grevillea xxii. 59 (non Leight. Lich. Fl. ed. 3,
374, fide Cromb. ms.). L. socialis Cromb. in Journ. Bot. xx.
275 (1882).
Crombie in ms. notes has rejected Leighton's description and thc
spccimen collected near the Wl'ekin, Shropshire. I have not seen
the specimen.
Hab. On dead mosses among rocks in an alpine loeality.-Distr.
Very scarce on one of the S. Grampians, Scotland.-B. M. Summit
of Craig Calliach, Perthshire.
Subseries III. GRAPHIDINElE.
Thallus shrubby or crustaceous, sometimes developed under
the bark (hypophlmodal), often little visible or wanting. Algal
cells (gonidia) Chlorophycem (Trentepohlia or rarely Palmellacem).
Apothecia roundish or irregular (ardellm), or linear (lirellm),
immarginate or with a proper margin only.
The Graphidinem are distinguished generally by the presence
of chrysogonidia (Trentepohlia) in the thallus, and by the form
of the apothecia. There are six families represented in the
British Isles :-
Thallus crustaceous, corticate on upper
surface............ ......... ........... ..... XXII. DmINACElE.
Thallus fruticose, strap·shaped or round·
ish, corticate on both surfaces..... XXIII. ROCOELLACElE.
Thallus crustaceous, not corticate.
Apothecia irregularly roundish,
usually marginate............ ......... XXIV. LECANACTIDACEM.
Apothecia irregularly roundish, linear
or stoll ate, immarginate............... XXV. ARTRONIACElE.
Apothecia linear, marginate............ XXVI. GRAPHIDACElE.
Apothecia aggregate in stroma·lIke
portions of the thallus ................. XXVII. CRIODECTONACElE.
Family XXII. DIRINACElE.
Thallus- crustaceous, attached by hyphre, corticate on the
upper surface, the cortex of closely packed upright hyphal
branches disposed at right angles to the surface (fastigiate).
Algal cells Trentepohlia. Apothecia discoid or somewhat elongate,
with proper and thalline margins; hypothecium and disc
dark-coloured; spores elongate, septate. Spermogones with
simple sterigmata and acicular bent aerogenous spermatia.